Bob Doyle

Bob Doyle

Our skin is our largest organ, covering about two square meters or roughly 20 square feet for a typical adult. Depending on our size, our skin weighs between 10 and 15 pounds.

Our skin creates melanin (pigment) to shield us from the sun’s rays. The thinnest skin is in our eyelids, about one-thousandth of an inch while our thickest skin is on our heels (both palms and feet).

The outer layer of skin is the epidermis whose boundary, the stratum corneum is dead cells that are replaced every month. These skin flakes, shed over a year’s time weigh about a pound.

Our skin’s next lowest layer is the dermis, containing blood vessels, lymph vessels, nerves and the roots of our hair follicles. The dermis also contains reservoirs of sweat and serbum. Underneath the dermis is the subcutaneous layer where fat is stored.

You have between two and five million hair follicles and even more sweat glands which pierce the epidermis. Every growing hair has a growing phase and a resting phase. Facial hair has a cycle of four weeks, but the scalp hair cycle may last six to seven years. Armpit hair lasts six months while leg hair has a cycle time of two months. Hair growth on a young adult grows about 0.01 inches a day.

You have between 100,000 to 150,000 hair follicles on your head. You lose an average between 50 and 100 head hairs a day. About 60% of men are nearly bald by the age of 50. 20% of men are bald by the age of 30.

An expensive and permanent solution is the transfer of hair plugs from the back of one’s head to near the front of the scalp. Twenty-five years ago the transfer of several hundred plugs in a matter of an hour using nitrous oxide (laughing gas) and sedatives cost $1,500.

One would need up to 10 of these procedures and several months of healing between each to restore a reasonable head of hair. Some doctors have turned to be specialists in this kind of hair restoration.

Some people turn to the use of propecia, to combat baldness. The problem with this drug is that it lowers your PSA (prostate specific antigen) reading and may mask the indication of prostate cancer.

There are two kinds of sweat glands: eccerine and apocrine. The first kind of sweat glands is what makes your shirt stick to your back on a hot, humid day. The apocrine glands are concentrated in your armpits and groin.

Sweat by itself is odorless; it requires bacteria to produce a smell. The two chemicals that cause the odor are isovaleric acid and methanedoil. You have about 100,000 bacteria per square cm (the size of a postage stamp) on your skin.

Even scrubbing your body with soap doesn’t make much of a dent in your skin’s bacterial population. A study at a New York University found that most people have about 200 different types of microbes on their skin.

Using antibacterial soaps is not the answer, as they eliminate good bacteria as well as bad. Hand sanitizers have the same problem. The Food and Drug Administration have banned 19 ingredients used in antibacterial soaps as they have not been proven safe on the long run.

In addition to microbes are tiny mites named Demodex folliculorum, who live in the hair follicles of your eyebrows.

Still available are the 2020 Night Sky Highlights, a two-page easy-to-understand document on the sun, moon, bright planets and stars. It features times of sunrise and sunset for all Sundays in eight communities in this area (including Cumberland). Request the Highlights for free from

SKY SIGHTS AHEAD: In mid-week, dawn begins around 6:30 a.m., sunrise about 7:34 a.m. and middle of the day at 12:24 p.m., Sunset about 5:15 p.m. and dusk ends about 6:15 p.m.

At the start of dawn, the stars begin to fade while at the end of dusk, the brighter stars can be seen. 

The brilliant planet Venus sets in the west-southwest at 8:15 p.m. The planet Mars rises in the southeast at 4:15 a.m. Go to for an easy-to-use Evening Sky Chart for the current month that you can print out.

Bob Doyle, retired science teacher at Frostburg State University, invites any readers comments and questions. E-mail him at He is available to clubs and student groups as a speaker on his column topics. 

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